1. Field of the Invention
The present invention relates to a testing unit and a connector testing apparatus using the same.
2. Description of the Related Art
Many industrial products have very small dimensional tolerances, and precise dimensional measurements of those products are required. However, conventional detecting means cannot detect dimensional deviations beyond tolerances with the precision that has been required in recent years. For example, a tolerance of about 0.6 mm conventionally has been accepted for parts of an electrical connector housing, such as a retainer or a cover. However, in recent years, this tolerance has been reduced to about 0.300 mm. Existing mechanical connector testing devices have been unable to detect dimensional deviations beyond such small dimensional tolerances due to deformation and shaking of the connector housing itself.
In view of the above, an object of the present invention is to provide a testing unit capable of securely testing a dimensional deviation of a specific part of a work piece beyond its tolerance. The invention also is directed to a connector testing apparatus that uses such a testing unit.
The invention is directed to a testing unit for detecting a dimensional deviation of a specific part of a work piece beyond its tolerance. The work piece may, for example, be a grommet or an outer tube used for an automotive vehicle. The testing unit comprises an elastic or resilient contact that can be brought elastically or resiliently into contact with the work piece. The testing unit also comprises a detecting portion on the contact for detecting the dimensional deviation of the work piece at the position where the contact engages the work piece. Accordingly, the detecting portion of the contact can reach a proper reference position for detecting dimensional deviations beyond a tolerance even if there is a variation in the final dimensions of the work piece, or if the work piece is shaky or deformed. The detecting portion detects a dimensional deviation of the specific part of the work piece at the contact position of the contact with the work piece. Thus, the deviation can be detected as precisely as possible.
The resilient contact preferably comprises an outer sleeve fixed in advance in a specific position and an inner sleeve that is mounted slideably to the outer sleeve. At least one of the sleeves is formed with a step that restricts the projecting distance of the inner sleeve toward the work piece. Thus, the inner sleeve is held resiliently in contact with the work piece for movement forward and backward in a testing state where the work is tested.
The inner sleeve preferably is fit for sliding movement in or on the outer sleeve. A biasing member preferably is provided between the inner sleeve and the outer sleeve for biasing the inner sleeve toward the work piece.
The detecting portion preferably comprises a switch mounted at a location on the inner sleeve that contacts the work piece in its proper position.
The elastic contact and the detecting portion preferably are provided in a testing device of a connector testing apparatus for testing a housing of a connector. In this embodiment, a dimensional deviation of the housing beyond its tolerance can be detected when the housing of the connector is tested.
The switch preferably comprises a fixed pin and a movable pin that is movable with respect to the fixed pin. The electric relationship between the fixed pin and the movable pin is changed when the switch contacts the work piece in its proper position.
The invention also is directed to a connector testing apparatus that has a fittable member with a locking portion that can be inserted into a housing in an insertion direction and then locked into the housing in a locking direction. The locking direction is aligned at an angle to the insertion direction. The testing apparatus comprises at least one testing unit for testing a mounted state of the fittable member mounted on the connector. The testing apparatus may further comprise a detecting portion for detecting an ajar state of the fittable member at a contact position where the resilient contact is in contact with the housing.
The connector testing apparatus may further comprise a connector receptacle for holding the connector and a testing device. The testing device substantially faces the connector receptacle and is adapted to test an electrical connection of the connector held by the connector receptacle. The testing apparatus further comprises means for displacing the connector receptacle and the testing device relative to each other between a separated state where they are spaced from each other and a testing state where they are adjacent to each other. A testing unit is in the testing device for testing a mounted state of the fittable member mounted on the connector held by the connector receptacle in the testing state. The elastic contact member preferably is moved in the locking direction for elastically contacting the housing of the connector held by the connector receptacle.
The fittable member may be a cover with a lock for locking terminals in the housing or a retainer for doubly locking the terminals already locked by locking portions in the housing.